This application is based upon and claims priority to German Patent Application 199 43 208.2 filed Sep. 9, 1999, which application is herein expressly incorporated by reference.
The invention relates to a drive assembly for an agricultural implement. The drive assembly has at least two implement portions. The first implement portion includes a first rotary driving device. The second implement portion has a second rotary driving device which is rotationally connected to the first rotary driving device by a shaft assembly. The second implement portion can be pivoted relative to the first implement portion from an active position into an inactive position about a pivot axis.
DE 196 40 888 C1 illustrates an agricultural implement which includes a first implement portion and a pivotable side part. In the operating position, the first implement portion is tilted downwards. In the transport position, the first implement portion is tilted upwards. A driveshaft with two shaft portions is provided to drive the tools associated with the side part. One shaft portion is associated with the first implement portion. The other shaft portion is associated with the side part of the agricultural implement. A coupling enables the two shaft portions to be aligned on a common longitudinal axis and to connect to one another in a rotationally fast way. Two coupling claws of the first shaft portion engage two coupling claws of the second shaft portion. In the engaged position, the two profiled shaft tubes, associated with the shaft portions, can move inside one another. When the side part is tilted upwards, the driveshaft cannot rotate and the shaft portions have to be separated to tilt the side part upwards.
DE 44 45 634 C2 illustrates a free-wheeling coupling which provides a driving connection for agricultural implement drives. The coupling provides two driving directions of rotation. The coupling has an inner ring and an outer ring. Pivotable locking pawls are loaded by springs towards a torque transmitting position. The inner ring is not intended to be rotated into a defined position.
It is an object of the present invention to propose a drive assembly for an agricultural implement where there is no need to separate the components of the driving connection. Also, there is no need to center the components to re-couple the second implement portion when transferring it from its rest position into the operating position.
In accordance with the invention, the drive assembly comprises at least two implement portions. The second implement portion is pivotable relative to the first implement portion around a pivot axis from an operational position into a rest position. The drive assembly includes a first rotary driving device coupled with the first implement portion. Also, a second rotary driving device is coupled with the second implement portion. A shaft assembly connects the first rotary driving device to the second rotary driving device. The shaft assembly has at least one first universal joint coupled with the first rotary driving device. The universal joint has a cross member with two pairs of arms centered on arm axes which extend perpendicularly relative to one another. A force-operated setting device enables the first universal joint to be transferred into a rotational position where one of its arm axes, in the direction of rotation, at least approaches a parallel line relative to the pivot axis.
An advantage of this embodiment is that the second implement portion is pivotable relative to the first implement portion up to a pivot angle of about 110xc2x0 around the pivot axis without a need to disconnect the drive connection. Accordingly, this eliminates the risk of the universal joint being destroyed due to an unfavorable angular position of the arm axes relative to the pivot axis.
According to a further embodiment of the invention, the shaft assembly can be transferred by the setting device into a rotational position. Here, the shaft assembly is between an arm axis of the first universal joint and a parallel line relative to the pivot axis. The parallel line extends through the point of intersection of the two arm axes. An angle of rotation exists with a maximum value of 15xc2x0. This ensures that the joint yokes do not contact one another if a pivot movement of the second implement portion occurs relative to the first implement portion.
In a preferred further embodiment, the setting device comprises a free-wheeling coupling and a power drive. The free-wheeling coupling has an inner ring connected in a rotationally fast way to one of the drive components. Thus, the free-wheeling coupling is attached to the first rotary driving device or one of the driving means attached thereto; to the second rotary driving device or one of the driving means attached thereto; or to the shaft assembly. Furthermore, the free-wheeling coupling includes an outer ring which is acted upon by the power drive for rotational adjustment purposes. The inner ring and the outer ring are arranged so as to be centered on an axis of rotation.
According to a preferred embodiment, one of the coupling parts of the free-wheeling coupling, preferably the inner ring or the outer ring, includes at least one pivotably supported and spring-loaded locking pawl. The locking pawl may engage at least one recess of the respective other coupling part. During operation, when the shaft connected to the free-wheeling coupling rotates in the driving direction of rotation, the locking pawl is not engaged. Accordingly, the inner ring of the free-wheeling coupling, which is connected to the shaft, freely rotates relative to the outer ring. When the drive is disconnected, the shaft assembly is in a rest position. Also, the outer part is simultaneously rotated by the power drive in the driving direction of rotation. Thus, the locking pawl connects the inner ring and the outer ring of the free-wheeling coupling. When a position of rotation is achieved where the locking pawl is able to engage, the shaft assembly is rotated into the desired position. The rotational path which the outer ring is able to cover with the help of the power drive is such that the desired position of rotation is always reached.
According to a preferred embodiment of the invention, the first rotary driving device or the second rotary driving device include a shaft. The inner ring of the free-wheeling coupling is connected in a rotationally fast way to the shaft. The inner ring is preferably associated with two locking pawls. The locking pawls are each arranged so as to be offset by 180xc2x0 around the axis of rotation of the shaft. The outer ring includes four recesses which are each arranged at 90xc2x0 around the axis of rotation.
According to a preferred embodiment of the invention, the power drive is a hydraulic cylinder. The cylinder is connected to the outer ring of the free-wheeling coupling. Thus, the cylinder is offset relative to the second axis of rotation and to the respective implement portion. The hydraulic cylinder includes a piston. A rotational movement of the outer ring relative to the inner ring of the free-wheeling coupling in the operational direction of rotation of the shaft connected to the inner ring occurs when the piston rod moves out of the cylinder. A single-action hydraulic cylinder is preferred for this function. Accordingly, under the influence of a spring, the hydraulic cylinder again assumes its moved-in position. A switching connection may be present between the hydraulic cylinder and the pivot drive of the agricultural implement. At least the drive component of the agricultural implement, which is attached to the free-wheeling coupling, has to be in its rest position before the hydraulic cylinder is actuated. Thus, the shaft assembly can be moved into the desired rotational position. While the second implement portion carries out a pivot movement relative to the first implement portion, the shaft assembly with the first universal joint is moved into a rotational position with one of the two arm axes of the cross member of the first universal joint approaching a line extending parallel relative to the pivot axis. The desired end position of rotation of the arm axes is reached when the angle between the first implement portion and the second implement portion reaches a maximum value of 60xc2x0.
From the following detailed description, taken in conjunction with the drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.